This invention is generally in the field of NOx emission abatement. More particularly, the present invention is directed to systems and methods for reducing NOx emissions from NOx producing sources.
NOx emissions are a concern for many industries, particularly in power-generating industries. NOx production is common in high-temperature combustion applications and/or with the combustion of nitrogen-bearing fuels. At high combustion temperatures, diatomic nitrogen in the combustion air may be oxidized to produce NOx. Nitrogen in the fuel may also be released as free radicals during combustion to form NOx. NOx emissions are generally known to cause acid rain as well as deleterious health side effects and are, therefore, a subject of regulatory scrutiny.
One common approach to NOx reduction involves the injection of a reducing agent over a catalyst to convert NOx to N2. Even more specifically, the use of ammonia with a selective catalytic reduction (“SCR”) catalyst is presently the most common approach to NOx reduction. In some applications, this approach may be effective for removing 80 to 95% of NOx from a gas stream; however, the use of an ammonia reactant may be a significant operating cost.
As such, it would be desirable to provide new systems and methods for NOx reduction. It would also be desirable to provide new systems and methods for NOx reduction that eliminate the need for or reduce the utilization of reducing reactants such as ammonia.